The present embodiments relate to a method for imaging during radiotherapy.
Radiotherapy is an established method, with which ionizing radiation is used in order to treat pathological tissue such as, for example, tumor tissue. The objective of radiotherapy is to irradiate the tissue to be treated with a sufficient therapeutic dose and, at the same time, to protect healthy surrounding tissue. The therapeutic effect is based in part on the fact that ionizing radiation acts differently on healthy and pathological tissue.
In order to provide that uncertainties in the positioning of the tissue to be treated, which may arise between a planning phase and a treatment phase for a variety of reasons, do not jeopardize the outcome of the treatment, safety margins, by which the target volume is enlarged, may be used.
Image guided radiation therapy (IGRT) enables uncertainties in the radiation of the target volume to be reduced and the accuracy of the radiation to be improved. IGRT enables the target volume, organs at risk (OAR) and healthy, surrounding tissue to be visualized before commencing, or during, radiation in order to open up the possibility of irradiating the target volume more accurately and using smaller safety margins.
During a fraction of the radiation, the patient may be positioned correctly at the start of the radiation. However, the imaging may also provide useful information during the radiation.
Methods, with which stereotactic images are prepared, are known. For example, X-ray sources may be installed on the roof of an irradiation chamber with oppositely disposed detectors on the floor. This permits projection imaging in order to obtain stereotactic information.